Literature | MOLNÁR-INSTITUTE

Journal of Chromatography A · 2017

Optimization of non-linear gradient in hydrophobic interaction chromatography for the analytical characterization of antibody-drug conjugates

Balázs Bobály, Giuseppe Marco Randazzo, Serge Rudaz, Davy Guillarme, Szabolcs Fekete

The goal of this work was to evaluate the potential of non-linear gradients in hydrophobic interaction chromatography (HIC), to improve the separation between the different homologous species (drug-to-antibody, DAR) of commercial antibody-drug conjugates (ADC). The selectivities between Brentuximab Vedotin species were measured using three different gradient profiles, namely linear, power function based and logarithmic ones. The logarithmic gradient provides the most equidistant retention distribution for the DAR species and offers the best overall separation of cysteine linked ADC in HIC. Another important advantage of the logarithmic gradient, is its peak focusing effect for the DAR0 species, which is particularly useful to improve the quantitation limit of DAR0. Finally, the logarithmic behavior of DAR species of ADC in HIC was modelled using two different approaches, based on i) the linear solvent strength theory (LSS) and two scouting linear gradients and ii) a new derived equation and two logarithmic scouting gradients. In both cases, the retention predictions were excellent and systematically below 3% compared to the experimental values.

Arabian Journal of Chemistry · 2017

Quality by design approach: Regulatory need

Jaiprakash N. Sangshetti, Mrinmayee Deshpande, Zahid Zaheer, Devanand B. Shinde, Rohidas Arote

In this era of competition quality has been given prime magnitude; failure to meet such quality allied goals produces massive shift of company in share of market. In this context pharmaceutical industry is utmost regulated industry as it is governed by authoritative regulatory bodies. “Quality could be planned and most of quality deficit arises in the way process is planned and developed”, this thought of well known quality expert Joseph Moses Juran gives foundation to the concept of quality by design (QbD). USFDA launched a pilot programme in 2005 to permit participating firms a prospect to submit chemistry, manufacturing, and controls (CMC) of NDA information representing application of QbD. Now USFDA is accelerating QbD drive by making warning to generic manufacturers from January 2013. QbD has its perspectives to contribute the drug design, development, and manufacture of high-quality drug products. In the present review basic consideration of the QbD approach, its historical background, and regulatory needs are discussed. In detail explanation of elements of QbD i.e. method intent, design of experiment, and risk assessment is given. Application of QbD to pharmaceutical and biopharmaceutical processes, development and unit operation associated with it are briefly mentioned. Detail account of QbD to analytical technique is explained thoroughly by referencing examples.

Journal of Pharmaceutical and Biomedical Analysis · 2017

A workflow for column interchangeability in liquid chromatography using modeling software and quality-by-design principles

Róbert Kormány, Katalin Tamás, Davy Guillarme, Szabolcs Fekete

The goal of the present study was to develop a generic workflow to evaluate the chromatographic resolution in a large design space and easily find some replacement column for the method. To attain this objective from a limited number of initial experiments, modern LC modeling software (Drylab) was employed to study the behaviour of the compounds and visually compare the parts of design spaces obtained with different columns, where a given criterion of critical resolution is fullfilled. A zone of robust space can then easily be found by overlapping design spaces. By using 50×2.1mm columns packed with sub–2μm fully porous particles (UHPLC), the resolution in the entire design space can be modeled on the basis of only 2–3h experimental work per column. To demonstrate the applicability of the developed procedure, amlodipine and its related pharmacopeia impurities were selected as a case study. It was demonstrated that two columns from different providers (Waters Acquity HSS C18, Thermo Hypersil Gold C18) can be interchanged, providing a sufficient resolution at the same working point and a high degree of robustness around this condition.

Journal of Pharmaceutical and Biomedical Analysis · 2017

Renewal of an old European Pharmacopoeia method for Terazosin using modeling with mass spectrometric peak tracking

Róbert Kormány, Imre Molnár, Jenő Fekete

An older method for terazosin was reworked in order to reduce the analysis time from 90min (2×45min) to below 5min. The method in European Pharmacopoeia (Ph.Eur.) investigates the specified impurities separately. The reason of the different methods is that the retention of two impurities is not adequate in reversed phase, not even with 100% water. Therefore ion-pair-chromatography has to be applied and since that two impurities absorb at low UV-wavelength they had to be analyzed by different method than the other specified impurities. In our new method we could improve the retention with pH elevation using a new type of stationary phases available for high pH applications. Also a detection wavelength could be selected that is appropriate for the detection and quantification of all impurities. The method development is the bottleneck of liquid chromatography even today, when more and more fast chromatographic systems are used. Expert knowledge with intelligent programs is available to reduce the time of method development and offer extra information about the robustness of the separation. Design of Experiments (DoE) for simultaneous optimization of gradient time (tG), temperature (T) and ternary eluent composition (tC) requires 12 experiments. A good alternative way to identify a certain peak in different chromatograms is the molecular mass of the compound, due to its high specificity. Liquid Chromatography–Mass Spectrometry (LC–MS) is now a routine technique and increasingly available in laboratories. In our experiment for the resolution- and retention modeling the DryLab4 method development software (Version 4.2) was used. In recent versions of the software the use of (m/z)-MS-data is possible along the UV-peak-area-tracking technology. The modelled and measured chromatograms showed excellent correlations. The average retention time deviations were ca. 0.5s and there was no difference between the predicted and measured Rs,crit −values.

Liquid Chromatography (Second Edition) · 2017

Chapter 14 - Method development in liquid chromatography

John W. Dolan, Lloyd R. Snyder, Salvatore Fanali, Paul R. Haddad, Colin F. Poole, Marja-Liisa Riekkola

A general approach to method development based on the concept of quality by design is described. The workflow includes problem definition, mode selection, selectivity optimization, system optimization, and method validation. Computer-assisted methods can support some of these decision steps minimizing the time required to build a robust method. The approach used is generally applicable, but practical illustrations will largely be restricted to isocratic and gradient elution methods in reversed-phase liquid chromatography. Critical parameters are identified as column selection, identification of the mobile-phase composition, gradient time, temperature, pH (for ionizable compounds), and buffer concentration. We focus on how to select these variables and their influence on the quality criteria for defining method suitability.

Journal of Pharmaceutical and Biomedical Analysis · 2017

Analysis of recombinant monoclonal antibodies in hydrophilic interaction chromatography: A generic method development approach

Balázs Bobály, Valentina D’Atri, Alain Beck, Davy Guillarme, Szabolcs Fekete

Hydrophilic interaction liquid chromatography (HILIC) is a well-established technique for the separation and analysis of small polar compounds. A recently introduced widepore stationary phase expanded HILIC applications to larger molecules, such as therapeutic proteins. In this paper, we present some generic HILIC conditions adapted for a wide range of FDA and EMA approved recombinant monoclonal antibody (mAb) species and for an antibody-drug conjugate (ADC). Seven approved mAbs possessing various isoelectric point (pI) and hydrophobicity as well as a cysteine conjugated ADC were used in this study. Samples were digested by IdeS enzyme and digests were further fragmented by chemical reduction. The resulting fragments were separated by HILIC. The main benefit of HILIC was the separation of polar variants (glycovariants) in a reasonable analysis time at the protein level, which is not feasible with other chromatographic modes. Three samples were selected and chromatographic conditions were further optimized to maximize resolution. A commercial software was used to build up retention models. Experimental and predicted chromatograms showed good agreement and the average error of retention time prediction was less than 2%. Recovery of various species and sample stability under the applied conditions were also discussed.

Liquid Chromatography · 2017

Chapter 1 - Milestones in the development of liquid chromatography

Lloyd R. Snyder, John W. Dolan, Salvatore Fanali, Paul R. Haddad, Colin F. Poole, Marja-Liisa Riekkola

The evolution of high-performance liquid chromatography is reviewed with an emphasis on the innovations that occurred in the technique in response to the sample needs. The general themes are the development and/or applications of the basic theory as catalyst for change, invention of new chromatographic modes, evolution of column technology, and the development and improvement of instrumentation. Steady progress in these areas rather than sudden change is responsible for the column chemistries, particle technology, instrumentation, and data handling tools available today.

Journal of Pharmaceutical and Biomedical Analysis · 2017

Separation of antibody drug conjugate species by RPLC: A generic method development approach

Szabolcs Fekete, Imre Molnár, Davy Guillarme

This study reports the use of modelling software for the successful method development of IgG1 cysteine conjugated antibody drug conjugate (ADC) in RPLC. The goal of such a method is to be able to calculate the average drug to antibody ratio (DAR) of and ADC product. A generic method development strategy was proposed including the optimization of mobile phase temperature, gradient profile and mobile phase ternary composition. For the first time, a 3D retention modelling was presented for large therapeutic protein. Based on a limited number of preliminary experiments, a fast and efficient separation of the DAR species of a commercial ADC sample, namely brentuximab vedotin, was achieved. The prediction offered by the retention model was found to be highly reliable, with an average error of retention time prediction always lower than 0.5% using a 2D or 3D retention models. For routine purpose, four to six initial experiments were required to build the 2D retention models, while 12 experiments were recommended to create the 3D model. At the end, RPLC can therefore be considered as a good method for estimating the average DAR of an ADC, based on the observed peak area ratios of RPLC chromatogram of the reduced ADC sample.

Journal of Pharmaceutical Analysis · 2017

Separation of atropisomers by chiral liquid chromatography and thermodynamic analysis of separation mechanism

Ling Zhang, Yue Hu, Elizabeth Galella, Frank P. Tomasella, William P. Fish

In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from a scientific and regulatory perspective. The compound of interest contains two stereogenic axes due to the hindered rotation around the single bonds connecting the aryl groups, which results in four potential configurational isomers (atropisomers). The separation of the four atropisomers is achieved on a derivatized β-cyclodextrin bonded stationary phase. Further investigation shows that low temperature conditions, including sample preparation (−70°C), sample storage (−70°C), and chromatographic separation (6°C), were critical to preventing interconversion. LC-UV-Laser Polarimetric analysis identified peak 1/2 as a pair of enantiomers and peak 3/4 as another. Thermodynamic analysis of the retention data indicated that the separation of the pairs of enantiomers is primarily enthalpy controlled as indicated by the positive slope of the van’t Huff plot. The difference in absolute Δ (Δ H), ranged from 2.20kJ/mol to 2.42kJ/mol.

Journal of Pharmaceutical and Biomedical Analysis · 2016

Practical method development for the separation of monoclonal antibodies and antibody-drug-conjugate species in hydrophobic interaction chromatography, part 1: optimization of the mobile phase

Marta Rodriguez-Aller, Davy Guillarme, Alain Beck, Szabolcs Fekete

The goal of this work is to provide some recommendations for method development in HIC using monoclonal antibodies (mAbs) and antibody-drug conjugates (ADCs) as model drug candidates. The effects of gradient steepness, mobile phase pH, salt concentration and type, as well as organic modifier were evaluated for tuning selectivity and retention in HIC. Except the nature of the stationary phase, which was not discussed in this study, the most important parameter for modifying selectivity was the gradient steepness. The addition of organic solvent (up to 15% isopropanol) in the mobile phase was also found to be useful for mAbs analysis, since it could provide some changes in elution order, in some cases. On the contrary, isopropanol was not beneficial with ADCs, since the most hydrophobic DAR species (DAR6 and DAR8) cannot be eluted from the stationary phase under these conditions. This study also illustrates the possibility to perform HIC method development using optimization software, such as Drylab. The optimum conditions suggested by the software were tested using therapeutic mAbs and commercial cysteine linked ADC (brentuximab-vedotin) and the average retention time errors between predicted and experimental retention times were ∼1%.

Advances in Chromatography, Volume 53 · 2016

Recent Advances in the Characterization and Analysis of Therapeutic Oligonucleotides by Analytical Separation Methods Coupling with Mass Spectrometry

Eli Grushka, Nelu Grinberg

Oligonucleotide therapeutics (OGNTs) are a class of short-chain oligonucleotides (OGNs) consisting typically of 15-50 nucleotide units in length. OGNTs are

Analyst · 2016

Computer assisted liquid chromatographic method development for the separation of therapeutic proteins

Eva Tyteca, Jean-Luc Veuthey, Gert Desmet, Davy Guillarme, Szabolcs Fekete

This review summarizes the use of computer assisted liquid chromatographic method development for the analytical characterization of protein biopharmaceuticals. Several modes of chromatography including reversed-phase liquid chromatography (RPLC), ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC) and some perspectives are discussed. For all these chromatographic modes, the most important variables for tuning retention and selectivity are exposed. Then, the retention models that were applied in the literature in RPLC, IEX and HIC are described and critically discussed. Finally, some representative examples of separation of therapeutic proteins and mAbs are shown, to illustrate the possibilities offered by the retention modeling approach. At the end, the reliability of the models was excellent, whatever the chromatographic mode, and the retention time prediction errors were systematically below 2%. In addition, a significant amount of time can be saved during method development and robustness testing.

Journal of Pharmaceutical and Biomedical Analysis · 2016

A platform analytical quality by design (AQbD) approach for multiple UHPLC-UV and UHPLC–MS methods development for protein analysis

Jianmei Kochling, Wei Wu, Yimin Hua, Qian Guan, Juan Castaneda-Merced

A platform analytical quality by design approach for methods development is presented in this paper. This approach is not limited just to method development following the same logical Analytical quality by design (AQbD) process, it is also exploited across a range of applications in methods development with commonality in equipment and procedures. As demonstrated by the development process of 3 methods, the systematic approach strategy offers a thorough understanding of the method scientific strength. The knowledge gained from the UHPLC-UV peptide mapping method can be easily transferred to the UHPLC–MS oxidation method and the UHPLC-UV C-terminal heterogeneity methods of the same protein. In addition, the platform AQbD method development strategy ensures method robustness is built in during development. In early phases, a good method can generate reliable data for product development allowing confident decision making. Methods generated following the AQbD approach have great potential for avoiding extensive post-approval analytical method change. While in the commercial phase, high quality data ensures timely data release, reduced regulatory risk, and lowered lab operational cost. Moreover, large, reliable database and knowledge gained during AQbD method development provide strong justifications during regulatory filling for the selection of important parameters or parameter change needs for method validation, and help to justify for removal of unnecessary tests used for product specifications.

Forensic Science International · 2016

In-silico optimisation of two-dimensional high performance liquid chromatography for the determination of Australian methamphetamine seizure samples

Luke M. Andrighetto, Niki K. Burns, Paul G. Stevenson, James R. Pearson, Luke C. Henderson, Christopher J. Bowen, Xavier A. Conlan

In-silico optimisation of a two-dimensional high performance liquid chromatography (2D-HPLC) separation protocol has been developed for the interrogation of methamphetamine samples including model, real world seizure, and laboratory synthesised samples. The protocol used Drylab® software to rapidly identify the optimum separation conditions from a library of chromatography columns. The optimum separation space was provided by the Phenomonex Kinetex PFP column (first dimension) and an Agilent Poroshell 120 EC-C18 column (second dimension). To facilitate a rapid 2D-HPLC analysis the particle packed C18 column was replaced with a Phenomenex Onyx Monolithic C18 withought sacrificing separation performance. The Drylab® optimised and experimental separations matched very closely, highlighting the robust nature of HPLC simulations. The chemical information gained from an intermediate methamphetamine sample was significant and complimented that generated from a pure seizure sample. The influence of the two-dimensional separation on the analytical figures of merit was also investigated. The limits of detection for key analytes in the second dimension determined for methamphetamine (4.59ÿ10⿿4M), pseudoephedrine (4.03ÿ10⿿4M), caffeine (5.16ÿ10⿿4M), aspirin (9.32ÿ10⿿4M), paracetamol (5.93ÿ10⿿4M) and procaine (2.02ÿ10⿿3M).

Journal of Pharmaceutical and Biomedical Analysis · 2016

Hydrophobic interaction chromatography for the characterization of monoclonal antibodies and related products

Szabolcs Fekete, Jean-Luc Veuthey, Alain Beck, Davy Guillarme

Hydrophobic interaction chromatography (HIC) is a historical strategy used for the analytical purification and characterization of proteins. Similarly to what can be done in reversed-phase liquid chromatography (RPLC), HIC is able to separate protein species based on their hydrophobicity, but using different conditions. Compared to RPLC, the main benefit of HIC is its ability to perform separations under non denaturing conditions (i.e. physiological pH conditions, ambient mobile phase temperature and no need for organic solvents) and so an orthogonal method. The goal of this review is to provide a general overview of theoretical and practical aspects of modern HIC applied for the characterization of therapeutic protein biopharmaceuticals including monoclonal antibodies (mAbs), antibody drug conjugates (ADCs) and bispecific antibodies (bsAbs). Therefore, method development approaches, state-of-the-art column technology, applications and future perspectives are described and critically discussed.

Toxicology and Applied Pharmacology · 2016

An extensive cocktail approach for rapid risk assessment of in vitro CYP450 direct reversible inhibition by xenobiotic exposure

Dany Spaggiari, Youssef Daali, Serge Rudaz

Acute exposure to environmental factors strongly affects the metabolic activity of cytochrome P450 (P450). As a consequence, the risk of interaction could be increased, modifying the clinical outcomes of a medication. Because toxic agents cannot be administered to humans for ethical reasons, in vitro approaches are therefore essential to evaluate their impact on P450 activities. In this work, an extensive cocktail mixture was developed and validated for in vitro P450 inhibition studies using human liver microsomes (HLM). The cocktail comprised eleven P450-specific probe substrates to simultaneously assess the activities of the following isoforms: 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 2J2 and subfamily 3A. The high selectivity and sensitivity of the developed UHPLC-MS/MS method were critical for the success of this methodology, whose main advantages are: (i) the use of eleven probe substrates with minimized interactions, (ii) a low HLM concentration, (iii) fast incubation (5min) and (iv) the use of metabolic ratios as microsomal P450 activities markers. This cocktail approach was successfully validated by comparing the obtained IC50 values for model inhibitors with those generated with the conventional single probe methods. Accordingly, reliable inhibition values could be generated 10-fold faster using a 10-fold smaller amount of HLM compared to individual assays. This approach was applied to assess the P450 inhibition potential of widespread insecticides, namely, chlorpyrifos, fenitrothion, methylparathion and profenofos. In all cases, P450 2B6 was the most affected with IC50 values in the nanomolar range. For the first time, mixtures of these four insecticides incubated at low concentrations showed a cumulative inhibitory in vitro effect on P450 2B6.

Food Microbiology · 2016

Inhibition mechanism of Listeria monocytogenes by a bioprotective bacteria Lactococcus piscium CNCM I-4031

Taous Saraoui, Papa Abdoulaye Fall, Françoise Leroi, Jean-Philippe Antignac, Sylvain Chéreau, Marie France Pilet

Listeria monocytogenes is a pathogenic Gram positive bacterium and the etiologic agent of listeriosis, a severe food-borne disease. Lactococcus piscium CNCM I-4031 has the capacity to prevent the growth of L. monocytogenes in contaminated peeled and cooked shrimp. To investigate the inhibititory mechanism, a chemically defined medium (MSMA) based on shrimp composition and reproducing the inhibition observed in shrimp was developed. In co-culture at 26 °C, L. monocytogenes was reduced by 3–4 log CFU g−1 after 24 h. We have demonstrated that the inhibition was not due to secretion of extracellular antimicrobial compounds as bacteriocins, organic acids and hydrogen peroxide. Global metabolomic fingerprints of these strains in pure culture were assessed by liquid chromatography coupled with high resolution mass spectrometry. Consumption of glucose, amino-acids, vitamins, nitrogen bases, iron and magnesium was measured and competition for some molecules could be hypothesized. However, after 24 h of co-culture, when inhibition of L. monocytogenes occurred, supplementation of the medium with these compounds did not restore its growth. The inhibition was observed in co-culture but not in diffusion chamber when species were separated by a filter membrane. Taken together, these data indicate that the inhibition mechanism of L. monocytogenes by L. piscium is cell-to-cell contact-dependent.

Journal of Pharmaceutical and Biomedical Analysis · 2016

Practical method development for the separation of monoclonal antibodies and antibody-drug-conjugate species in hydrophobic interaction chromatoraphy, part 2: Optimization of the phase system

Alessandra Cusumano, Davy Guillarme, Alain Beck, Szabolcs Fekete

The goal of this second part was (i) to evaluate the performance of commercially available HIC columns and (ii) to develop a fast and automated “phase system” (i.e. stationary phase and salt type) optimization procedure for the analytical characterization of protein biopharmaceuticals. For this purpose, various therapeutic mAbs (denosumab, palivizumab, pertuzumab, rituximab and bevacizumab) and a cysteine linked ADC (brentuximab-vedotin) were selected as model substances. Several HIC column chemistries (butyl, ether and alkylamide) from different providers were evaluated in four different buffer systems (sodium acetate, sodium chloride, ammonium acetate and ammonium sulfate). As stationary phases, the historical TSK gel Butyl NPR phase and the brand new Thermo MAbPac HIC-10 were found to be the most versatile ones in terms of hydrophobicity, peak capacity and achievable selectivity. As salt types, ammonium sulfate and sodium acetate were found to be particularly well adapted for the analytical characterization of mAbs and ADCs, but it is important to keep in mind that a concentration 2 to 3-times higher of sodium acetate versus ammonium sulfate is required to achieve a similar retention in HIC. After selection of the most appropriate phase systems, the optimization of the separation can be carried out by computer assisted retention modeling in a high throughput manner.

Analytica Chimica Acta · 2015

Effect of temperature on acid–base equilibria in separation techniques. A review

Leonardo G. Gagliardi, Marcos Tascon, Cecilia B. Castells

Studies on the theoretical principles of acid–base equilibria are reviewed and the influence of temperature on secondary chemical equilibria within the context of separation techniques, in water and also in aqueous-organic solvent mixtures, is discussed. In order to define the relationships between the retention in liquid chromatography or the migration velocity in capillary electrophoresis and temperature, the main properties of acid–base equilibria have to be taken into account for both, the analytes and the conjugate pairs chosen to control the solution pH. The focus of this review is based on liquid–liquid extraction (LLE), liquid chromatography (LC) and capillary electrophoresis (CE), with emphasis on the use of temperature as a useful variable to modify selectivity on a predictable basis. Simpliﬁed models were evaluated to achieve practical optimizations involving pH and temperature (in LLE and CE) as well as solvent composition in reversed-phase LC.

Atmospheric Environment · 2015

Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation

Ahmed A. Reda, J. Schnelle-Kreis, J. Orasche, G. Abbaszade, J. Lintelmann, J. M. Arteaga-Salas, B. Stengel, R. Rabe, H. Harndorf, O. Sippula, T. Streibel, R. Zimmermann

Gas phase emission samples of carbonyl compounds (CCs) were collected from a research ship diesel engine at Rostock University, Germany. The ship engine was operated using two different types of fuels, heavy fuel oil (HFO) and diesel fuel (DF). Sampling of CCs was performed from diluted exhaust using cartridges and impingers. Both sampling methods involved the derivatization of CCs with 2,4-Dinitrophenylhydrazine (DNPH). The CCs-hydrazone derivatives were analyzed by two analytical techniques: High Performance Liquid Chromatography–Diode Array Detector (HPLC–DAD) and Gas Chromatography–Selective Ion Monitoring–Mass Spectrometry (GC–SIM–MS). Analysis of DNPH cartridges by GC–SIM–MS method has resulted in the identification of 19 CCs in both fuel operations. These CCs include ten aliphatic aldehydes (formaldehyde, acetaldehyde, propanal, isobutanal, butanal, isopentanal, pentanal, hexanal, octanal, nonanal), three unsaturated aldehydes (acrolein, methacrolein, crotonaldehyde), three aromatic aldehyde (benzaldehyde, p-tolualdehyde, m,o-molualdehyde), two ketones (acetone, butanone) and one heterocyclic aldehyde (furfural). In general, all CCs under investigation were detected with higher emission factors in HFO than DF. The total carbonyl emission factor was determined and found to be 6700 and 2300 μg kWh−1 for the operation with HFO and DF respectively. Formaldehyde and acetaldehyde were found to be the dominant carbonyls in the gas phase of ship engine emission. Formaldehyde emissions factor varied from 3870 μg kWh−1 in HFO operation to 1540 μg kWh−1 in DF operation, which is 4–30 times higher than those of other carbonyls. Emission profile contribution of CCs showed also a different pattern between HFO and DF operation. The contribution of formaldehyde was found to be 58% of the emission profile of HFO and about 67% of the emission profile of DF. Acetaldehyde showed opposite behavior with higher contribution of 16% in HFO compared to 11% for DF. Heavier carbonyls (more than two carbon atoms) showed also more contribution in the emission profile of the HFO fuel (26%) than in DF (22%).

Decades of chromatography research done with DryLab®.

Optimization of non-linear gradient in hydrophobic interaction chromatography for the analytical characterization of antibody-drug conjugates

Quality by design approach: Regulatory need

A workflow for column interchangeability in liquid chromatography using modeling software and quality-by-design principles

Renewal of an old European Pharmacopoeia method for Terazosin using modeling with mass spectrometric peak tracking

Chapter 14 - Method development in liquid chromatography

Analysis of recombinant monoclonal antibodies in hydrophilic interaction chromatography: A generic method development approach

Chapter 1 - Milestones in the development of liquid chromatography

Separation of antibody drug conjugate species by RPLC: A generic method development approach

Separation of atropisomers by chiral liquid chromatography and thermodynamic analysis of separation mechanism

Practical method development for the separation of monoclonal antibodies and antibody-drug-conjugate species in hydrophobic interaction chromatography, part 1: optimization of the mobile phase

Recent Advances in the Characterization and Analysis of Therapeutic Oligonucleotides by Analytical Separation Methods Coupling with Mass Spectrometry

Computer assisted liquid chromatographic method development for the separation of therapeutic proteins

A platform analytical quality by design (AQbD) approach for multiple UHPLC-UV and UHPLC–MS methods development for protein analysis

In-silico optimisation of two-dimensional high performance liquid chromatography for the determination of Australian methamphetamine seizure samples

Hydrophobic interaction chromatography for the characterization of monoclonal antibodies and related products

An extensive cocktail approach for rapid risk assessment of in vitro CYP450 direct reversible inhibition by xenobiotic exposure

Inhibition mechanism of Listeria monocytogenes by a bioprotective bacteria Lactococcus piscium CNCM I-4031

Practical method development for the separation of monoclonal antibodies and antibody-drug-conjugate species in hydrophobic interaction chromatoraphy, part 2: Optimization of the phase system

Effect of temperature on acid–base equilibria in separation techniques. A review

Gas phase carbonyl compounds in ship emissions: Differences between diesel fuel and heavy fuel oil operation